/*-------------------------------------------------------------------------
 *
 * gistvalidate.c
 *      Opclass validator for GiST.
 *
 * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *      src/backend/access/gist/gistvalidate.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "access/amvalidate.h"
#include "access/gist_private.h"
#include "access/htup_details.h"
#include "catalog/pg_amop.h"
#include "catalog/pg_amproc.h"
#include "catalog/pg_opclass.h"
#include "catalog/pg_opfamily.h"
#include "catalog/pg_type.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/regproc.h"
#include "utils/syscache.h"


/*
 * Validator for a GiST opclass.
 */
bool
gistvalidate(Oid opclassoid)
{// #lizard forgives
    bool        result = true;
    HeapTuple    classtup;
    Form_pg_opclass classform;
    Oid            opfamilyoid;
    Oid            opcintype;
    Oid            opckeytype;
    char       *opclassname;
    HeapTuple    familytup;
    Form_pg_opfamily familyform;
    char       *opfamilyname;
    CatCList   *proclist,
               *oprlist;
    List       *grouplist;
    OpFamilyOpFuncGroup *opclassgroup;
    int            i;
    ListCell   *lc;

    /* Fetch opclass information */
    classtup = SearchSysCache1(CLAOID, ObjectIdGetDatum(opclassoid));
    if (!HeapTupleIsValid(classtup))
        elog(ERROR, "cache lookup failed for operator class %u", opclassoid);
    classform = (Form_pg_opclass) GETSTRUCT(classtup);

    opfamilyoid = classform->opcfamily;
    opcintype = classform->opcintype;
    opckeytype = classform->opckeytype;
    if (!OidIsValid(opckeytype))
        opckeytype = opcintype;
    opclassname = NameStr(classform->opcname);

    /* Fetch opfamily information */
    familytup = SearchSysCache1(OPFAMILYOID, ObjectIdGetDatum(opfamilyoid));
    if (!HeapTupleIsValid(familytup))
        elog(ERROR, "cache lookup failed for operator family %u", opfamilyoid);
    familyform = (Form_pg_opfamily) GETSTRUCT(familytup);

    opfamilyname = NameStr(familyform->opfname);

    /* Fetch all operators and support functions of the opfamily */
    oprlist = SearchSysCacheList1(AMOPSTRATEGY, ObjectIdGetDatum(opfamilyoid));
    proclist = SearchSysCacheList1(AMPROCNUM, ObjectIdGetDatum(opfamilyoid));

    /* Check individual support functions */
    for (i = 0; i < proclist->n_members; i++)
    {
        HeapTuple    proctup = &proclist->members[i]->tuple;
        Form_pg_amproc procform = (Form_pg_amproc) GETSTRUCT(proctup);
        bool        ok;

        /*
         * All GiST support functions should be registered with matching
         * left/right types
         */
        if (procform->amproclefttype != procform->amprocrighttype)
        {
            ereport(INFO,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("operator family \"%s\" of access method %s contains support procedure %s with different left and right input types",
                            opfamilyname, "gist",
                            format_procedure(procform->amproc))));
            result = false;
        }

        /*
         * We can't check signatures except within the specific opclass, since
         * we need to know the associated opckeytype in many cases.
         */
        if (procform->amproclefttype != opcintype)
            continue;

        /* Check procedure numbers and function signatures */
        switch (procform->amprocnum)
        {
            case GIST_CONSISTENT_PROC:
                ok = check_amproc_signature(procform->amproc, BOOLOID, false,
                                            5, 5, INTERNALOID, opcintype,
                                            INT2OID, OIDOID, INTERNALOID);
                break;
            case GIST_UNION_PROC:
                ok = check_amproc_signature(procform->amproc, opckeytype, false,
                                            2, 2, INTERNALOID, INTERNALOID);
                break;
            case GIST_COMPRESS_PROC:
            case GIST_DECOMPRESS_PROC:
            case GIST_FETCH_PROC:
                ok = check_amproc_signature(procform->amproc, INTERNALOID, true,
                                            1, 1, INTERNALOID);
                break;
            case GIST_PENALTY_PROC:
                ok = check_amproc_signature(procform->amproc, INTERNALOID, true,
                                            3, 3, INTERNALOID,
                                            INTERNALOID, INTERNALOID);
                break;
            case GIST_PICKSPLIT_PROC:
                ok = check_amproc_signature(procform->amproc, INTERNALOID, true,
                                            2, 2, INTERNALOID, INTERNALOID);
                break;
            case GIST_EQUAL_PROC:
                ok = check_amproc_signature(procform->amproc, INTERNALOID, false,
                                            3, 3, opckeytype, opckeytype,
                                            INTERNALOID);
                break;
            case GIST_DISTANCE_PROC:
                ok = check_amproc_signature(procform->amproc, FLOAT8OID, false,
                                            5, 5, INTERNALOID, opcintype,
                                            INT2OID, OIDOID, INTERNALOID);
                break;
            default:
                ereport(INFO,
                        (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                         errmsg("operator family \"%s\" of access method %s contains function %s with invalid support number %d",
                                opfamilyname, "gist",
                                format_procedure(procform->amproc),
                                procform->amprocnum)));
                result = false;
                continue;        /* don't want additional message */
        }

        if (!ok)
        {
            ereport(INFO,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("operator family \"%s\" of access method %s contains function %s with wrong signature for support number %d",
                            opfamilyname, "gist",
                            format_procedure(procform->amproc),
                            procform->amprocnum)));
            result = false;
        }
    }

    /* Check individual operators */
    for (i = 0; i < oprlist->n_members; i++)
    {
        HeapTuple    oprtup = &oprlist->members[i]->tuple;
        Form_pg_amop oprform = (Form_pg_amop) GETSTRUCT(oprtup);
        Oid            op_rettype;

        /* TODO: Check that only allowed strategy numbers exist */
        if (oprform->amopstrategy < 1)
        {
            ereport(INFO,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("operator family \"%s\" of access method %s contains operator %s with invalid strategy number %d",
                            opfamilyname, "gist",
                            format_operator(oprform->amopopr),
                            oprform->amopstrategy)));
            result = false;
        }

        /* GiST supports ORDER BY operators */
        if (oprform->amoppurpose != AMOP_SEARCH)
        {
            /* ... but must have matching distance proc */
            if (!OidIsValid(get_opfamily_proc(opfamilyoid,
                                              oprform->amoplefttype,
                                              oprform->amoplefttype,
                                              GIST_DISTANCE_PROC)))
            {
                ereport(INFO,
                        (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                         errmsg("operator family \"%s\" of access method %s contains unsupported ORDER BY specification for operator %s",
                                opfamilyname, "gist",
                                format_operator(oprform->amopopr))));
                result = false;
            }
            /* ... and operator result must match the claimed btree opfamily */
            op_rettype = get_op_rettype(oprform->amopopr);
            if (!opfamily_can_sort_type(oprform->amopsortfamily, op_rettype))
            {
                ereport(INFO,
                        (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                         errmsg("operator family \"%s\" of access method %s contains incorrect ORDER BY opfamily specification for operator %s",
                                opfamilyname, "gist",
                                format_operator(oprform->amopopr))));
                result = false;
            }
        }
        else
        {
            /* Search operators must always return bool */
            op_rettype = BOOLOID;
        }

        /* Check operator signature */
        if (!check_amop_signature(oprform->amopopr, op_rettype,
                                  oprform->amoplefttype,
                                  oprform->amoprighttype))
        {
            ereport(INFO,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("operator family \"%s\" of access method %s contains operator %s with wrong signature",
                            opfamilyname, "gist",
                            format_operator(oprform->amopopr))));
            result = false;
        }
    }

    /* Now check for inconsistent groups of operators/functions */
    grouplist = identify_opfamily_groups(oprlist, proclist);
    opclassgroup = NULL;
    foreach(lc, grouplist)
    {
        OpFamilyOpFuncGroup *thisgroup = (OpFamilyOpFuncGroup *) lfirst(lc);

        /* Remember the group exactly matching the test opclass */
        if (thisgroup->lefttype == opcintype &&
            thisgroup->righttype == opcintype)
            opclassgroup = thisgroup;

        /*
         * There is not a lot we can do to check the operator sets, since each
         * GiST opclass is more or less a law unto itself, and some contain
         * only operators that are binary-compatible with the opclass datatype
         * (meaning that empty operator sets can be OK).  That case also means
         * that we shouldn't insist on nonempty function sets except for the
         * opclass's own group.
         */
    }

    /* Check that the originally-named opclass is complete */
    for (i = 1; i <= GISTNProcs; i++)
    {
        if (opclassgroup &&
            (opclassgroup->functionset & (((uint64) 1) << i)) != 0)
            continue;            /* got it */
        if (i == GIST_DISTANCE_PROC || i == GIST_FETCH_PROC)
            continue;            /* optional methods */
        ereport(INFO,
                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                 errmsg("operator class \"%s\" of access method %s is missing support function %d",
                        opclassname, "gist", i)));
        result = false;
    }

    ReleaseCatCacheList(proclist);
    ReleaseCatCacheList(oprlist);
    ReleaseSysCache(familytup);
    ReleaseSysCache(classtup);

    return result;
}
